GrailAtlasAn independent mechanical watch reference
Deutsch
Mass-produced#4 in family

Live pricing is coming soon. Get notified when it is available for this reference.

Movement tier: unclassified · caliber Piaget Cal. 1200P: in-house automatic, 28,800bph, 44h PR, 27j; only 2.35mm thick, a world record for thinnest self-winding caliber for years; ultra-flat Altiplano benchmark · 44h power reserve
Versatile size: fits most wrists (6–7.5 in / 15–19 cm)
38 mm case. The sweet spot for the broadest range of wrist sizes. Neither too dainty nor too bold.

Not yet rated

Community + OSINT signals haven’t landed for this reference yet. We don’t publish a rating against zero signal: the number would mean nothing. Editorial body + caliber + market value still surface above; ratings appear once the signal corpus does.

Search pre-owned listings

Chrono24
eBay (sold listings)
WatchBox

Authentication

Cal. 1200P at 2.35mm is the thinnest automatic movement in production; crown seating and gasket integrity are critical on this ultra-thin case.

Known issues in the market
  • The thin case makes crystal seating and crown gasket integrity critical; any crown that sits proud or at an angle has a worn or missing gasket.
  • The total watch height is 5.25mm; any Altiplano 38mm automatic measuring noticeably more than 5.5mm at its thickest point is incorrect.
AreaWhat to checkWhat is correctRed flag
crownCrown seating flush with caseCrown sits perfectly flush with the case side at rest; no proud seating or angular misalignmentCrown that sits proud of the case or at any angle; visible gap between crown and case indicates gasket failure
crystalSapphire crystal seatingCrystal is perfectly seated with no visible gap at the bezel; no chip or crack at any edgeCrystal with visible gap at seating; any chip especially near the crystal edge where ultra-thin cases are most vulnerable
movementCal. 1200P via casebackExhibition caseback showing Cal. 1200P at 2.35mm height; Piaget decoration visible on rotor and bridgesNon-Piaget movement; any movement with a visible thickness greater than 2.35mm; solid caseback on exhibition-spec model
Common legitimate replacements
  • Crown gaskets on ultra-thin cases are service parts that require factory or specialist replacement; do not use a watchmaker without ultra-thin experience.
  • Service intervals on Cal. 1200P should follow Piaget recommendations; the ultra-thin architecture requires specialized tools and technique.
Expert resources: Piaget Altiplano technical documentation at piaget.com. TimeZone Piaget subforum for Cal. 1200P service and crown gasket references.

Authentication guide

Last reviewed June 2026

The Altiplano 38mm Automatic carries caliber 1200P, at 2.35mm among the thinnest self-winding movements in production. Total case height is 5.34mm. Slimness is the authentication anchor: any watch claiming this reference that sits measurably thicker is suspect.

Known reproduction risks

toggle
HIGH RISK

Undecorated movement bridges

  • Bridges visible through caseback have brushed-only or unfinished surfaces
  • No Cotes de Geneve striping visible under loupe
  • No anglage (beveling) on bridge edges

Piaget movement finishing is non-negotiable. Every genuine Piaget across all price points has decorated bridges. Undecorated bridges mean the movement is not from Piaget.

HIGH RISK

Case too thick

  • Watch case measurably over 6mm in total height
  • Caseback sits noticeably proud rather than flush
  • Watch feels like a conventional dress watch in thickness -- the Altiplano 1200P is noticeably thinner than conventional pieces
MEDIUM

Non-gold rotor

  • Steel or brass-colored rotor instead of gold-toned 18k oscillating weight
  • Rotor has no Piaget branding or logo
  • Rotor geometry differs from the standard Piaget oscillating weight profile

Dial variants by era

toggle
EraDescriptionIdentifiers
2010 to presentWhite or silver lacquered dial. Clean, uncluttered layout with applied index markers. No date complication on the primary 38mm Altiplano. "PIAGET" at 12, "SWISS MADE" at 6. Hour and minute hands in a polished finish. The overall presentation is extremely spare -- the design philosophy is to not distract from the thinness of the case.
  • Applied index markers at each hour (no Arabic numerals)
  • "PIAGET" in block capitals at 12 o'clock
  • No date window -- clean dial face
  • White or silver dial surface without texture
  • Slim hour and minute hands with polished finish
  • Case in 18k white gold -- steel is not standard for this reference

Service part flags

toggle
Movement through caseback

Original: Caliber 1200P is 2.35mm thick. It is visible through the display caseback. The rotor is an 18k gold oscillating weight. Piaget movement finishing: chamfered and polished bridges with Cotes de Geneve decoration. The bridges must be visibly decorated -- undecorated bridges in a claimed Piaget are an immediate flag.

Replacement tells
  • Undecorated movement bridges -- any genuine Piaget has Cotes de Geneve and anglage on the bridges
  • Steel rotor rather than 18k gold oscillating weight
  • Rotor with no Piaget engraving or incorrect Piaget logo proportions
  • Movement sitting at noticeably different height than 2.35mm -- a different movement will appear taller
Case thickness

Original: Total case height is 5.34mm. This is unusually thin in the hand. When laid on a flat surface, the watch barely lifts off the table. The movement is partially recessed into the caseback plane.

Replacement tells
  • Case height measurably above 6mm
  • Watch feels substantially thicker in the hand than expected for an ultra-thin dress piece
  • Caseback sits proud of the case band rather than flush or slightly recessed

Case back markings

toggle
2010 to present
  • Caliber 1200P designation engraved on caseback or movement
  • "PIAGET" with the Piaget logo
  • Water resistance: 20m
  • Reference G0A39112 with serial number
  • "OR BLANC 18K" indicating white gold case
  • "SWISS MADE" inscription

Movement tells

toggle
  • Caliber 1200P has a 44-hour power reserve. A watch stopping after 20-24 hours from full wind has either a different movement or a badly worn mainspring.
  • The 18k gold rotor is visible through the caseback. At rest, it should settle with the weight at the bottom. When moving the watch, it should swing freely with only the lightest friction.
  • Piaget specifies Cotes de Geneve on all movement bridges. Under a loupe through the caseback, the decoration should be clearly visible as parallel linear stripes on each bridge surface. This is non-negotiable on any genuine Piaget.
Sources: Piaget official; Monochrome -- Piaget Altiplano Ultra-Thin.

You might also like

Piaget
Altiplano
Ref. G0A43112
Piaget
Altiplano
Ref. G0A43001
Piaget
Altiplano
Ref. G0A45502
Piaget
Altiplano
Ref. G0A42105
A. Lange & Söhne Lange 1 Ref. 191.039, silver dial, gold-rose case
A. Lange & Söhne
Lange 1
Ref. 191.039
A. Lange & Söhne Saxonia Thin Ref. 211.027, silver dial, gold-rose case
A. Lange & Söhne
Saxonia
Ref. 211.027

Buying guidance

← Back to Grail Atlas